A program of adjuvant immunotherapy and chemoimmunotherapy following potentially curative surgery for colorectal cancer has been initiated at M.D. Anderson in April of 1973. Patients of the Dukes' C classification were selected for the study. With the longest follow-up of thirty months, the interim results of this study show a statistically significant benefit from both BCG and the combination of 5FU plus BCG, both in terms of disease-free interval and survival compared to a group of historical controls who had only surgery for the same condition. More specifically, a total of 83 patients were entered on the study until the end of August, 1975. Thirty-three patients received BCG alone, and 50 patients received the combination of 5FU plus BCG. A total of 14 patients have already relapsed, and of those, six received BCG and eight received the combination of 5FU plus BCG. The disease-free interval curves for both BCG and 5FU plus BCG are significantly better than that of the historical controls. Of the total of 83 patients, only two had died. Both of these patients have received BCG. No deaths occurred among the patients who received the 5FU plus BCG. The survival curves of both BCG, and 5FU plus BCG are significantly better than the survival curve for the historical controls. More patients and a longer follow-up are needed to confirm and establish these results. Bibliographic references: Mavligit, G.M., Gutterman, J.U., Burgess, M.A. et. al: Immunotherapy: Its Possible Application in the Management of Large Bowel Cancer, American Journal of Digestive Diseases 19:1047-1053, 1974.